An API for attaching to and interacting with the V8 debugger.
Last updated 6 years ago by anandthakker .
MIT · Repository · Bugs · Original npm · Tarball · package.json
$ cnpm install debugger-api 
SYNC missed versions from official npm registry.


A thin adapter that gives direct access to node-inspector's backend.

Normally, node-inspector is acting both as a client--to a process run with node --debug--and also as a server--serving up a web(kit) frontend. This package gives direct access to the debugger client without having to start up the server.


npm install debugger-api


var DebuggerApi = require('debugger-api');

// make sure node is running in debug mode: node --debug-brk=5000
// then:
var dbugger = new DebuggerApi({debugPort: 5000});

// enable debugging.

// initial breakpoint (because of debug-brk)
dbugger.once('Debugger.paused', function(firstBreak) {

  var scriptId = firstBreak.callFrames[0].location.scriptId,
      url = dbugger.scripts.findScriptByID(scriptId).url;

    url: url,
    lineNumber: 4
  dbugger.on('Debugger.paused', function (pausedResult) {


{ callFrames:
   [ { callFrameId: '0',
       functionName: '',
       location: { scriptId: '46', lineNumber: 4, columnNumber: 2 },
       scopeChain: [ [Object], [Object] ],
        { type: 'object',
          subtype: undefined,
          objectId: '1',
          className: 'Object',
          description: 'Object' } },
     { callFrameId: '1',
       functionName: 'Module._compile',
       location: { scriptId: '36', lineNumber: 455, columnNumber: 25 },
       scopeChain: [ [Object], [Object], [Object] ],
        { type: 'object',
          subtype: undefined,
          objectId: '7',
          className: 'Object',
          description: 'Object' } },
  reason: 'other',
  data: null,
  hitBreakpoints: [ 2 ] }

See the tests for more.


The returned object exposes the same methods as node-inspector's DebuggerAgent, but inherits from EventEmitter and emits events (see below) rather than sending signals to a frontend.



A node-inspector ScriptManager instance.


enable(null, function(error, result))

Enable debugging.

disable(null, function(error, result))

Disable debugging.

pause(null, function(error, result))

Pause execution.

resume(null, function(error, result))

Resume execution. Emits Debugger.resumed

stepOver(null, function(error, result))

Step over current line. Emits Debugger.resumed

stepInto(null, function(error, result))

Step into current line, creating a new call frame. Emits Debugger.resumed

stepOut(null, function(error, result))

Step out of current call frame. Emits Debugger.resumed

continueToLocation({location: location}, function(error, result))

NOTE: this appears to be broken at the moment. Need to research the underlying node-inspector code.

location is in the form {scriptId, lineNumber, columnNumber}. Emits Debugger.resumed

getScriptSource({scriptId: scriptId}, function(error, result))

Get the script source by scriptId. See also ScriptManager, available as scripts. result is {scriptSource: source}

setScriptSource({scriptId: id, scriptSource: source}, function(error, result))

Set the script source (even mid-execution!).
result is {callFrames: [...], result: result} TODO: what is result?

setPauseOnExceptions({state: 'all' | 'uncaught'}, function(error, result))

TODO: cb(?)

setBreakpointByUrl(params, function(error, result))

Set a breakpoint.

params = {url: scriptUrl,
          lineNumber: line number,
          columnNumber: column number,
          condition: stop condition}

reponse is {breakpointId: id, locations: [...]}

removeBreakpoint({breakpointId: id}, function(error, result))

Remove a breakpoint based on breakpointId. TODO: expose a way to query current list of breakpoints.

setBreakpointsActive({active: boolean}, function(error, result))

Toggle breakpoints.

evaluateOnCallFrame({expression: string, callFrameId: frameId}, function(error, result))

Eval the given expression in the context of a specific call frame. result is {result: inspectorResult | errorMessage, wasThrown: boolean }

getFunctionDetails({functionId: id}, function(error, result))

result is a function details object.

restartFrame({callFrameId: id}, function(error, result))

Restart execution of the given call frame. result is {callFrames: [...], result: result} TODO: what is result?

setVariableValue(params, function(error, result))

Set variable value. Might not be supported, depending on V8 build/version.

params = {variableName, newValue, scopeNumber, callFrameId}

TODO: what is result?



Current Tags

  • 0.1.2                                ...           latest (6 years ago)

3 Versions

  • 0.1.2                                ...           6 years ago
  • 0.1.1                                ...           6 years ago
  • 0.1.0                                ...           6 years ago
Maintainers (1)
Today 0
This Week 0
This Month 0
Last Day 0
Last Week 0
Last Month 1
Dependencies (2)
Dev Dependencies (1)
Dependents (2)

Copyright 2014 - 2016 © |